Curved conduit



Sept. 18.', 1934.,y vF. JHIGLEY 'l f 1,974,109

cuRVED coNDUIT Filed Dec. 16, 1931 INVENTOR ATTORNEU Patented Sept. 18, 1934 murs sTATss PATENT orties CURVED CONDUIT Frank It. Higley, Cleveland Heights, Ohio Application December 16, 1931, Serial No. 581,342 t 6" claims. (o1. 137-112) Y This invention relates to improvements in the type of conduit having a curved way, thatv is, to a device having a through passageway, the entrance to which is adapted to receive flow from one direction; the conduit being adapted to change the direction of this flow, so that the conduit discharge opening, at the opposite end of the way, will discharge the flow in another direction.Y A typical example is the ordinary elbow pipe tting adapted to interconnect a pair of straight -pipe lengths angulariy related but in a common plane.

. A consideration oi such a pipe tting will make evident that, in its normal functioning, the path of a unit of volume, in the stream through the curve of the system will be entirely dependent upon where such unit enters the curved tting. If the unit enters at the outside of the bend it will travel through the fitting along the outside of the curvature of the latter. But if the unit enters at the insideV of the bend, if the'velocity offiow be suniciently low, such unit will travel along the inside of the bend; and its path through the conduit will consequently be much shorter than that of the unit iirst considered. 1f the velocity and mass oi the second considered unit be suniciently high, it will tend to maintain its original direction of motion and pass across the conduit on a line beginning at the inside of the bend but ending at the outside of the bend. In either event it will be apparent that flow through the fitting will be accompanied by considerable relative motion between the units of volume in the stream, producing a turbulence which materially impairs the efficiency of operation.

It is the object of my invention to eliminate such turbulence. Briefly, I accomplish this by providing means whereby in the stream, all units with reference to the sectional area transverse to the now, will have paths of equal length through the curve.

More specically, to this end, I provide, in a conduit having a curved way of substantially uniform sectional area, means in said way for causing the absolute path of now of a unit of volume in the stream along said way, to be helical, with such angular advancement about the mean path of said way, as said mean path extends along the curve of said way, that the absolute paths of all units of volume are substantially equal.

The invention has particular application where large masses are to be handled, as in turbine draft tubes; where high velocities are met, as in steam lines and the air inlet passages of internal combustion engines; and where the nature of the materials to be handled makes the handling dini--y cult, such as in devices for feeding coal or other solids in pieces.

The exact nature of this invention together with further objects and advantages'thereof will be apparent from the following description taken in connection with the accompanying drawing, wherein two applications or" the invention are conventionally illustrated, Figs. 1-4 inclusive illustrating the invention as applied to a 90 or elbow bend and Figs. 5-7 illustrating the invention as applied to a 180 or return bend. More specically, Fig. l is a View in section, of a conduit showing (in elevation) partition means therein, and in broken lines arrows indicating paths of flow therethrough; Figs. 2-and 3 are opposite end views of the complete conduit indicated in Fig. 1; Fig. 4 is a transverse section as in the plane of line 4-4, Fig. l; Fig. 5 is a View similar to Fig.V 1 but of a conduit having a way of 180 curvature; Fig. 6 is an end view of the same, and Fig. 7 is a section asin 'the plane ofl line 7 7, Fig. 5. With reference now to Figs. 1-4 of the drawing, 1 is a conduit having a curved way of circular sectional area, the curvature of saidway being on an arc of 90. Thus, in the positionl of Fig. 1, the conduit has a horizontal inlet direction and a vertical outlet direction.

Within said way I arrange a partition member 2 extending -diametrically across the way in every section thereof transverse to the general path therethrough, and extending along the way throughout the latter. Also, the partition memloer 2 has a twist as indicated in the drawing, such that its transverse direction at the discharge end of the conduit is disposed 180 from that at the entrance thereto, with reference to the curved center line of the way.

Thus the general curved way through the conduit is actually divided into two passages, A and B, one on either side of the partition 2. These passages are also curved. They are in fact arranged helically in twisted relation, with 180 of angular advancement about the mean rpath of the way as said mean path extends along the inside of the curve of the conduit but the discharge end of the passage B is at the outside of the curve of the conduit. Consequently flow through the conduit will be as indicated by the arrows cb-a and b b, Fig. 1.

With reference now to Figs. 5-7, the conduit la is similar to the conduit 1 except that it has 180 of extent. In other words, its way is curved in a half circle so that the conduit has parallel entrance and discharge directions. The partition 2a is` likewise similarly diametrically disposed, with a twist, as is the partition 2. The total twist of the partition 2a is still 180, so that the amount o twist per unit of advancement along the mean path of travel is only y2 that of the partition 2.2 Still the curved way of the conduit is divided into a pair of passages C and D arranged helically in twisted relation, with 180 of angular advancement about the mean path of the way as said mean path extends along the curve of the way; and consequently the actuall paths of flow through the conduit will be as indicated by the arrows Fig. 5, the arrow c-c`Y indicating the path of ow through theione passage C and the arrow d-d indicating that through the passage D.

The employment of the partition means 2 shown, is not essential to my invention. The result of equalizing paths of flow as described, could be accomplished by equivalent structure such as by otherwise deforming the section of the curvedV Way through the conduit. Although desirable, it is not essential that the partition means 2 be diametrically disposed as described nor indeed is it necessary that only a single partition means be employed. Thus any plurality `of helically disposed inwardly extending ribs might serve the purpose, or the conduit might merely be deformed asto present a attened or square section, the section twisting as it advances. Nor is it essential, although desirable, -that the partition 2 at its ends lie as illustrated, in planes transverse to that of the curvature of the conduit, provided the total twistv of the partition or its equivalent deformation be 180.

In the embodiments illustrated in the drawing, the conduit itself might conceivablyr be of `cast metal and the partition 2 of relatively thin sheet metal, secured as by welding. Obviously, however, the parts might be integral and of' any other suitable material.

The twist, or rate of angular advancement' of the partition means 2 or its equivalent, is in the ordinary application preferably not uniform along the length of the curve. Instead it desirably increases from zero at each end to a maximum amount intermediate the ends; so that in straight pipe lengths which may lead to and from the curved conduit section, ilow will be in straight lines without twist, and the least energy will be absorbed in passing around the bend.

What I claim is:

1. In a conduit having a curved way of the class described, helical guide means in said way for causing the absolute path of flow of a unit of volume of a stream moving along said way to be helicalkwith substantially 180 cf angular advancement, about the mean path of said way as said mean pathextends along the curve of said way.

2.- In a conduit having a curved way, helical guide partition means in said way arranged to impart a h'alf revolution of motion about the mean path of now, toilow generally alongl the curve of said way.

3. In a conduit providing a curved way, helical guide means deforming saidwayA into-aplurality of passages arranged helically in twisted relation, withi 180 ofV angular advancement about the mean path of said wayl as said mean path extends alongA the curve of said way.

4. In a conduit having al curved way, diametrical guide partition means therein having a twist Hof'180 along'- the curve of saidway.

5. In a conduit having a' curved wayy of the class described, helical guide vane means disposed to cause the absolute path of flow'oi a unit of volume of a stream moving along said wayto be helical with substantially 180 of angular advance-V ment, about the mean path of said way as said mean path extends along the curve of said-way. 6. In a conduit having a curved way of the class described, helical guide means for causing the absolute path of flow of a' unit of volume of a stream movingalong said way to be helical with substantially 180 of angular advancement, about the mean path of said way as said mean path extends along the curve of said way.

FRANK R. HIGLEY. 

